1. Technical Field
The present invention relates to a liquid storage container such as an ink cartridge and a method of refilling a liquid into the liquid storage container.
2. Related Art
In the past, as a liquid ejecting apparatus for ejecting liquid drops from a nozzle of a liquid ejection head, an ink jet printer was known. Some ink jet printers have an ink supply system of an off-carriage type for mounting the ink cartridge on a position other than a carriage. In a case where the ink supply system of the off-carriage type is mounted, a large capacity ink cartridge can be provided to perform printing on a large sheet. Moreover, the ink cartridge can be not mounted to reduce the size of the carriage, thereby miniaturizing and sliming the ink jet printer.
In the ink supply system of the off-carriage type, for example, the ink cartridge is mounted on a printer body. Ink is supplied from the ink cartridge to a sub-tank or a printing head mounted in the carriage through an ink supply tube.
Such an ink cartridge is disclosed in JP-A-2002-19136. In the ink cartridge, an ink pack is held in a lower case, an elastic material such as foamed polystyrene is mounted, and an opening of the lower case is sealed by a sealing film to fix an upper case.
Since the ink pack is deformed due to a pressurizing air with lead-out of ink, the entire length of the ink pack full of the ink is considerably different from that of the ink pack in which the ink is empty. Accordingly, the difference in the entire lengths becomes considerable if the ink pack has a more capacity. For example, the difference in the entire lengths is about 1 cm. The rear end of the ink pack is a sealing joint portion, and it is more difficult for the rear end of the ink pack to be formed, comparing to an area which is not adhered.
In the past, the difference in the entire lengths of the ink packs is not required to be taken into consideration to design the size of the lower case since the ink pack full of ink is received in the lower case and the difference in the entire lengths can be ignored if the capacity of the ink pack is small.
However, if the capacity of the ink pack becomes increased and the entire length of the ink pack becomes expanded with the lead-out of ink from the ink pack, the rear end of the sealing joint portion may collide with the inner wall of the lower case. In this case, a free space of the rear end of the sealing joint portion is insufficient. Accordingly, since the sealing joint portion is not freely displaced, the free displacement of the ink pack may deteriorate. As a result, an amount of remaining ink becomes irregular when the deformation of the ink pack deteriorates.
Recently, the liquid level detecting unit is mounted in the ink cartridge. However, if the amount of remaining ink becomes irregular due to a difference in the deformation of the ink pack, it is difficult to design a threshold value of end detection or near end detection in the liquid level detecting unit. As a result, since the amount of ink remaining in the ink pack becomes large, it is not desired for a user.
The sealing joint portion displaced at the time the ink pack is deformed is not limited to the rear end of the ink pack, but may be adhered to both edges in accordance with an ink pack type. The sealing joint portions of both the edges can be also displaced when the ink is led out.